[CentOS] same Old question: 32 bits VS 64 bits on database performance

[Ken Price]

> We have several large projects will use ORACLE 10Gr2
> database with CENTOS 4.X.  Does anyone have
> performance report on 32 Bits O.S. (with 32 bit
> ORACLE) VS 64 bits?

I don't have any "report" per se, however, I have production  
experience with Oracle 9i, 9iR2, 10g, and 10gR2 on RedHat 7.3, CentOS  
3.X, and CentOS 4.X (32 and 64-bit).  Typically speaking, there isn't  
a huge increase in performance moving from 32-bit to 64-bit (Dell  
PowerEdge 2950).  I'd guess it's around 5-10% on the same hardware.   
However, the scalability of 64-bit - especially with regards to memory  
usage - should make this a no-brainer.  ALWAYS go with 64-bit where  
possible for databases and application servers.

If you are trying to same money and stick to older 32-bit hardware,  
there are of course workarounds for the memory limitations of the  
32-bit OS using "hugepages".
See the following:
http://www.puschitz.com/TuningLinuxForOracle.shtml#LargeMemoryOptimization

-Ken